Clinton and Sanders just had the election's most explosive exchange to date

After a string of debates where Hillary Clinton and Bernie Sanders discussed (and occasionally disagreed about) the fine points of progressive policy, the two finally had a full-fledged throwdown Thursday night.

Clinton accused Sanders of going negative on the campaign trail, telling the Vermont Senator at the Democratic debate that his campaign was smearing her name.

"I think it's time to end the very artful smear that you and your campaign have been carrying out in recent week," Clinton said after Sanders talked about getting money out of politics.

Sanders has boasted about not receiving money from Wall street, and has pointed out in recent weeks that Clinton has received large sums in exchange for speaking.

"Sen. Sanders has said he wants to run a positive campaign. I’ve tried to keep my disagreements over issues, but time and time again, by innuendo and by insinuation there is this attack that he is putting forth," Clinton said.

"Which really comes down to anyone who ever took donations or speaking fees from interest groups has to be bought, and I absolutely reject that Senator. I really don’t think those attacks by insinuation are worthy of you," Clinton continued.

Then she leveled the challenge: "If you have something to say, say it. But I have never changed a view or a vote because of a donation I've received."